Hi Guys;
I need to understand something. please help me establish an understanding.
i would try to share a block diagram of my service that is required to be provisioned over an mpls core back bone.
Customer_Multi_layer_Switch----Customer's-_Managed_CPE--------Ingress_PE------MPLS_Cloud------Egress_PE-----2xL2_SWITCH----Voice_Server/SBC
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Session Border controllers
Now customer multilayer switch has internal networks direcetly connected to it (varous voice platforms and video conferencing servicers live on these networks). If i have those networks as routed vlans, I can route them using bgp with Customer's managed CPE device; over layer 3 trunks (using sub-interfaces with dot 1 q encapsulatoion for each routable vlan and ip addresses).
CPE has a vrf for this customer. It populates this vrf with routes coming into it over bgp from Customer switch. I am assuming that these routes would have the dot1q tag associated with them in layer 2 header due to the encapsulation used on layer 3 trunks between Customer switch and Managed CPE.
The Ingress_PE exports the routes to MP-BGP, and the routes reach the Egress_PE.
The Egress_PE puts them into the Customer VRF. Now this Customer traffic needs to go to the SBC/Session border controller via intermediary layer 2 switches. Egress PE connects to these Layer 2 switches on one side and the SBC connects to th same SBC switch on the other side. ( I can have redundancy protocols running running between these Layer 2 switches, but i want to keep the flow simple for my understanding).
My question is:
- how would the Egress PE associate routes in a VRF with a VLAN? How does PE know that a route in a particular vrf also belongs to a certain VLAN (is my assumtion above correct: assumption that these routes would have the dot1q tag associated with them in layer 2 header due to the encapsulation used on layer 3 trunks between Customer switch and Managed CPE). How would PE read the VLAN TAG? I think PEs are only layer 3 devices, they do not use mac switching! Unless i am missing something or there is a way to do that. If there is a way to do that then i would like to know excatly how would that mapping occur (mapping from vrf to vlan)
- would I have to define the customer vlans on Egress PE and Ingress PE?
- how do i trunk those customer vlans between Egress PE and Intermediary switches?
If I can understand the flow of traffic and its treatment from client edge to sbc, i can apply the same logic in the revere direction. I would greatly appreciate if you can include some configuration examples in your response for teh steps i had losted above.
Thanks in advance